Making its commercial debut, an upgraded Falcon 9 rocket blasted away from Space Launch Complex 40 at Cape Canaveral today on SpaceX’s first mission to deliver a satellite to geostationary transfer orbit (GTO). Deploying a communications satellite for SES S.A., the launch marks a significant milestone for the once upstart company’s pursuit of the commercial launch market.

Today’s launch was critical to the future of SpaceX, which has over 10 commercial satellites on its books for flight in the coming years. It is equally important for company founder Elon Musk’s plans to make Falcon the preferred low-cost alternative to competitors such as the United Launch Alliance Atlas V and European Ariane 5 launch vehicles and capture a large share of the commercial market.

“As always, SpaceX remains committed to delivering the safest, most reliable launch vehicles on the market today. We appreciate SES’s early confidence in SpaceX and look forward to launching additional SES satellites in the years to come.”

Launch had originally been scheduled for last Monday, but was called off in the final minutes when abnormal pressure readings were noticed in the first stage liquid oxygen tank. Because the FAA wouldn’t issue a commercial launch license authorizing launch on the two days either before or after Thanksgiving (due to heavy air travel), SpaceX rescheduled the launch for Thanksgiving Day in what would have been the first Thankgsiving space launch launch from Cape Canaveral since 1959.

The countdown proceeded smoothly on Thursday and the start command was issued to Falcon’s 9 Merlin engines on time at 5:39 p.m. EST. However, the engines shutdown immediately after, forcing an on-the-pad abort similar to what has occurred on past Falcon missions.

A first look at the telemetry data showed that a slower than normal buildup of thrust in the first stage caused computers to shut them down rather than allow Falcon to blast off with a potential problem that could have cost the mission.

“Launch aborted by autosequence due to slower than expected thrust ramp. Seems ok on closer inspection. Cycling countdown,” Elon Musk said in a post on Twitter.

The count was recycled for another attempt, but, as the end of the launch window approached, controllers scrubbed for the day.

Musk followed up with more details as engineers analyzed the cause of Thursday’s scrub and prepared to try again.

“Abort was caused by oxygen in ground side TEA-TEB. Upper stage on separate internal circuit, so doesn’t face same risk,” Musk posted on Saturday.

Technicians cleaned the engines and replaced the gas generator on the center Merlin over the weekend and reset for another launch attempt on Tuesday.

“All known rocket anomalies resolved. Will spend another day rechecking to be sure. Launch attempt tmrw eve w Wed as backup,” said Musk.

Finally, After a week’s worth of delays, Falcon roared off the launch pad this evening, lifting off at 5:41 p.m. EST. Climbing slowly at first – it took 10 seconds to clear the lightning towers around the launch pad – the 224-foot tall rocket’s Merlin 1D engines lit up the dusk with flame as long as the rocket itself and sent a thunderours roar cascading across the landscape.

The rocket reached the speed of sound a minute later and cameras mounted on the outside of the rocket showing Earth below as it traveled east into nighttime.

The SES-8 mission required a dual-burn profile for Falcon’s upper stage, equipped with one Merlin engine. The first burn, lasting approximately 5 minutes, placed the stage and spacecraft into a preliminary orbit.

After the first shutdown, the rocket coasted until it reached halfway around the world, where it fired up again for a second burn that placed SES-8 into a highly elliptical supersynchronous geostationary transfer orbit with a high point of 50,0000 miles – a quarter of the way to the Moon – and a low point just over 200 miles high.

Restarting the engine on the upper stage was another first for the mission. Restart capability is necessary for Falcon to become a viable option for geosynchronous spacecraft. A test of this capability on the inaugural flight of the upgraded Falcon did not go well. Cold temperatures froze the upper stage igniter and prevented a relight.

Today, engine restart appeared perfect and SES-8 was released from the uppwer stage shortly after. Initial indications are that 6,918 pound SES-8 separated cleanly and is operating normally in orbit.

“Early in the initial check-out and testing process, the SES-8 mission is proceeding smoothly,” said Mr. Christopher Richmond, Orbital’s Senior Vice President of Communications Satellite Programs. “We are proud to continue to be a part of the SES team, helping increase communications capacity to meet the rapidly growing demand for telecommunications services in South Asia and Indo-China.”

The spacecraft will use its own thrusters to conduct five burns over the next two weeks, using the energy gained by being launched to 50,000 miles to assist in changing its orbital inclination from 21 degrees to zero while moving into a circular geostationary orbit 22,300 miles high. At the conclusion of these maneuvers, SES-8 will settle into its final location at 95 degrees east longitude. After a series of checkouts, it will be placed into operation to serve customers over southeast Asia including Vietname, Thailand and India and will operate co-located with SES’ NSS 6 satellite at the same location.

Romain Bausch, President and CEO of SES, stated, “SES’s maiden launch on board a Falcon 9 rocket is yet another example of our company’s spirit of innovation and advancement of the commercial space industry. We congratulate the SpaceX team for the success of a challenging launch campaign and our longstanding supplier Orbital for innovating with us in exploring new paths to orbit while delivering a brand-new, state-of-the-art satellite for Asia.”

“Our customers are looking forward to the new capacity, and we are delighted that SES, in collaboration with SpaceX and Orbital, is all set to deliver following today’s successful launch,” said Bausch. Through the co-location with NSS-6 at 95 degrees East, SES-8 will not only provide incremental high performance capacity, notably for DTH services, it will also create greater reliability and additional security for customers. The SES-8 satellite will significantly contribute to SES’s growing presence in Asia-Pacific.”

SES-8 was manufactured by Orbital Sciences Corporation and is the sixth STAR ™ satellite ordered by SES. An Orbital Sciences GEOStar-2 spacecraft, it is a hybrid Ku- and Ka-band spacecraft based on Orbital’s Enhanced STAR 2.4 bus.

SES-8 carries 24 active Ku-band transponders of 36 or 54 Mhz capacity switchable among 33 channels and two beams. Certain channels in each beam are cross-strapped to multiple frequency bands, enabling flexibility for new services. In the addition, the spacecraft features a Ka-band payload. The spacecraft generates approximately five kilowatts of payload power and features two 2.5 x 2.7 meter super elliptical deployable reflectors and a 1.45 meter fixed, nadir antenna.